Trends in engine design have been driven, in part, by a desire to reduce overall vehicle weight, generally and engine component weight, specifically. Engine intake manifolds have been the focus of substantial weight reduction efforts as manufacturers have adopted the use of non-traditional, light-weight materials. Polymers such as nylon are currently used in the manufacture of several intake manifolds. Aside from the weight advantage, plastics also facilitate the molding of complex structures prevalent in high-performance applications.
Detrimental to the optimization of plastic intake manifolds are other, manifold mounted components such as the throttle body and exhaust gas recirculation valves which require special reinforcement of the manifold structure along with an attendant weight increase. For instance, as throttle activities have become increasingly automated, throttle body weight has increased dramatically. If the throttle body mass must be supported by a plastic intake manifold, the structural requirements of the manifold dictate an increase in weight without which the throttle body is subjected to substantial vibration. In the case of EGR, plastic throttle bodies may require reinforcement in the area of exhaust gas introduction due to the temperatures.